Additive manufacturing systems that generate three-dimensional objects on a layer-by-layer basis have been proposed as a potentially convenient way to produce three-dimensional objects in small quantities. These systems typically receive a definition of the three-dimensional object in the form of an object model. This object model is processed to instruct an additive manufacturing system to produce the object using one or more build materials. There are many different types of additive manufacturing system. The processing of the object model may vary based on the type of additive manufacturing system.